In the production of dentures in a dental laboratory, a "working model" which reproduces the teeth and jaw proportions of a patient as closely as possible is the most important prerequisite. For this purpose, a negative form is first produced by the dentist in the mouth of the patient using so-called impression materials. The initially plastic workable impression material is introduced into the patient's mouth on an impression plate and solidified as much as possible to an elastic material. This represents the negative form when removed. This mold could then be finally filled with model material, thus resulting in a working model.